WASHINGTON -- Scientists who cultured human stem cells from discarded embryos and aborted fetuses told a Senate panel yesterday that their research could yield life-saving therapies, including a treatment for Parkinson's disease within a decade.

Acknowledging that their work poses tough moral questions, the researchers said they neither created nor destroyed life in their efforts to grow tissues that could transplanted into patients suffering from a variety of ailments.

"I firmly believe this research holds potential for the treatment of catastrophic disease and injuries that afflict humans," said Dr. John Gearhart, an obstetrician-gynecologist from the Johns Hopkins School of Medicine.

Using aborted fetuses, Gearhart was able to obtain and grow embryonic stem cells, primitive cells that generate brain, bone, blood and other cell types. Scientists are studying ways to direct the stem cells to become the type of cells they want, tailor-made for transplant.

The hearing, before an Appropriations subcommittee chaired by Republican Arlen Specter of Pennsylvania, promised to be the first of several aimed at helping Congress decide whether the National Institutes of Health should support embryonic stem cell research.

In 1995, Congress banned the use of federal funds for research that makes use of human embryos, but there is no similar ban against studies that use fetal tissue.

Funding ban lamented

"The number of diseases that can be treated will increase exponentially" with federal funding, said Dr. James A. Thomson of the University of Wisconsin. "The current ban in the U.S. on the use of federal funding for human embryo research discourages the majority of the best U.S. researchers from advancing this promising area of medical research."

Thomson derived stem cells from embryos that had gone unused at in-vitro fertilization clinics in Israel.

Scientists have defended the use of fetal tissue, saying it is not objectionable because the fetuses weren't created for the purpose of science. Women decided to have abortions before they were asked to donate fetal tissue for research, Gearhart told the committee.

Gearhart and others scientists said Parkinson's patients could be among the first to benefit from embryonic stem cells grown in laboratories. The work could also yield treatments for Alzheimer's, Huntington's and heart disease, and for muscular dystrophy and diabetes.

Gearhart said a Parkinson's treatment could be ready within "several years," and Thomson suggested a timetable of "five to 10 years."

Richard M. Doerflinger, representing the National Conference of Catholic Bishops, argued that such research is morally indefensible as long as cells are derived from elective abortions or from embryos created at in-vitro fertilization clinics.

Speaking for the bishops' anti-abortion committee, Doerflinger said Gearhart's work was intriguing because it opened the possibility that stem cells could be derived from accidental miscarriages or ectopic pregnancies. In those cases, he said, scientists would not encourage the willful destruction of human life.

"It could be the kind of thing we've been looking for to provide useful stem cell lines without creating or destroying early human life," Doerflinger said.

Gearhart said it would be difficult to get enough tissue that way because miscarriages and ectopic pregnancies are usually treated on an emergency basis. "It's been hard enough to work out the logistics" of obtaining tissue from abortions that are scheduled, he said.

NIH Director Harold Varmus said the research holds great promise.

'Breakthrough' foreseen

"Within the course of the next decade or so, and with appropriate cadre of investigators, many diseases could be treated if not cured," Varmus said. "The development of cell lines that may produce almost every tissue of the human body is an unprecedented scientific breakthrough."

The Hopkins and Wisconsin teams have obtained their funding from Geron Corp., a California biotechnology company. Gearhart said he also plans to file a grant application with the NIH.

Sen. Tom Harkin said it is "morally wrong to prevent or delay our world-class scientists from building on this progress."

"As long as research is conducted in an ethically validated manner, it should be allowed to go forward, and it should receive federal support," the Iowa Democrat said.